Two times a day there's a daily bijuu that spawn in Konoha, Suna, or Kiri its either Kurama, Shukaku, or Isobu to participate in daily bijuu you need to be 800 level or higher. Then the next step is to find them and defeat them with other players.
You can find informations such as Map, Time, and FAQ lower.

FAQ:

1. Question: Is there PVP on the event?
Answer: No, there's NO PVP at the event place, but there's PVP everywhere around.

2. Question: Who get's the reward?
Answer: Everybody gets a reward, you get it in a bag after defeating the bijuu, however its random what you get in the bag.

3. Question: What time do they spawn?
Answer: You can check that in the Time section lower.

4. What are tails about?
Answer: Tails are the only reward from bijuu that you get always, they are used in missions in the later game phase.